U.S. patent application number 13/429847 was filed with the patent office on 2013-09-26 for pretreatment of biomass using thermo mechanical methods before gasification.
This patent application is currently assigned to SUNDROP FUELS, INC.. The applicant listed for this patent is Robert S. Ampulski, Freya Kugler, Joel K. Monteith, John T. Turner. Invention is credited to Robert S. Ampulski, Freya Kugler, Joel K. Monteith, John T. Turner.
Application Number | 20130248767 13/429847 |
Document ID | / |
Family ID | 49210897 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130248767 |
Kind Code |
A1 |
Ampulski; Robert S. ; et
al. |
September 26, 2013 |
PRETREATMENT OF BIOMASS USING THERMO MECHANICAL METHODS BEFORE
GASIFICATION
Abstract
An integrated plant generates syngas from biomass, where the
integrated plant includes a Thermo Mechanical Pulping (TMP)
process, a biomass gasifier, a methanol synthesis process, and a
liquid fuel generation process. Biomass is received as a feedstock
in the TMP process. The biomass is pre-treated in the TMP process
for subsequent supply to the biomass gasifier by using a
combination of heat, pressure, moisture, and mechanical agitation
that are applied to the biomass to make the biomass into a pulp
form. The TMP process breaks down a bulk structure of the received
biomass, at least in part, by applying steam to degrade bonds
between lignin and hemi-cellulose from cellulose fibers of the
biomass. Next, the broken down particles of the biomass are reacted
in a biomass gasification reaction at a temperature of greater than
700 degrees C. to create syngas components, which are fed to a
methanol synthesis process.
Inventors: |
Ampulski; Robert S.;
(Fairfield, OH) ; Turner; John T.; (West Chester,
OH) ; Monteith; Joel K.; (Bethel, OH) ;
Kugler; Freya; (Conifer, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ampulski; Robert S.
Turner; John T.
Monteith; Joel K.
Kugler; Freya |
Fairfield
West Chester
Bethel
Conifer |
OH
OH
OH
OH |
US
US
US
US |
|
|
Assignee: |
SUNDROP FUELS, INC.
Longmont
CO
|
Family ID: |
49210897 |
Appl. No.: |
13/429847 |
Filed: |
March 26, 2012 |
Current U.S.
Class: |
252/373 ;
422/162 |
Current CPC
Class: |
C10G 3/00 20130101; Y02E
50/32 20130101; C10J 2300/0916 20130101; C10L 1/06 20130101; Y02E
50/30 20130101; B01J 2208/00513 20130101; B01J 2208/00504 20130101;
C10J 2300/1246 20130101; Y02P 20/145 20151101; C10J 3/62 20130101;
C10J 2300/0906 20130101; C10J 2300/1269 20130101; C10J 2300/1665
20130101; B01J 2208/00132 20130101; B01J 8/12 20130101; Y02E 50/18
20130101; C10L 9/083 20130101; B01J 8/087 20130101; Y02E 50/10
20130101; C07C 29/1518 20130101; Y02P 30/20 20151101; C10J 3/485
20130101; C10J 3/74 20130101; D21B 1/12 20130101; C07C 29/1518
20130101; C07C 31/04 20130101 |
Class at
Publication: |
252/373 ;
422/162 |
International
Class: |
C01B 3/02 20060101
C01B003/02; B01J 7/00 20060101 B01J007/00 |
Claims
1. An integrated plant to generate syngas from biomass, comprising:
a Thermo Mechanical Pulping unit having an input cavity to receive
biomass as a feedstock, a steam supply input, and two or more
stages to pretreat the biomass for subsequent supply to a biomass
gasifier, where the stages use a combination of heat, pressure,
moisture, and mechanical agitation that are applied to the biomass
to make the biomass into a pulp form, where the thermo mechanical
pulping process breaks down a bulk structure of the received
biomass, at least in part, by applying steam from the steam supply
input to degrade bonds between lignin and hemi-cellulose from
cellulose fibers of the biomass; and where the biomass gasifier has
a reactor configured to react particles of the biomass broken down
by the two or more stages of the Thermo Mechanical Pulping unit and
those biomass particles are subsequently fed to a feed section of
the biomass gasifier, where the biomass gasifier has a high
temperature steam supply input and one or more regenerative
heaters, and in the presence of the steam the particles of the
biomass broken down by the Thermo Mechanical Pulping unit are
reacted in the reactor vessel in a rapid biomass gasification
reaction at a temperature of greater than 700 degrees C. in less
than a five second residence time in the biomass gasifier to create
syngas components, including hydrogen (H2) and carbon monoxide
(CO), which are fed to a methanol (CH3OH) synthesis reactor.
2. The integrated plant of claim 1, where the biomass into a pulp
form from the Thermo Mechanical Pulping unit is sent a torrefaction
unit to under go torrefaction to pyrolyze biomass at a temperature
of less than 700 degrees C. for a preset amount of time and then
sent onto the biomass gasifier, where the two or more stages of the
Thermo Mechanical Pulping unit includes a steam tube stage and a
refiner unit stage, where the steam tube stage has the input cavity
to receive chips of the biomass and the steam supply input to apply
the steam into a vessel containing the chips of biomass at an
elevated temperature of 130 to 200 degrees C. at a pressure between
70 and 110 PSI, where the chips of biomass with softened lignin are
then fed from the steam tube stage to the refiner unit stage, which
is at the same pressure as the steam tube stage, where a mechanical
separator is configured to further to cooperate with the steam to
separate cellulose fibers of the biomass into 1) three or more
individual bundles of fibers, 2) individual strands of fibers, and
3) any combination of both.
3. The integrated plant of claim 1, where the two or more stages of
the Thermo Mechanical Pulping unit include a steam tube stage and a
refiner unit stage, where the steam tube stage has the steam
applied to the biomass at a temperature above a glass transition
point of lignin to soften the lignin so the cellulose fibers of the
biomass can easily be mechanically stripped apart from the biomass
in chip form in the refiner unit stage, where the steam tube stage
is configured to receive chips of biomass including leaves,
needles, bark, and wood, and then the chips of biomass are heated
to greater than 150.degree. C. using the steam at greater than 70
psi for about 90 to 180 seconds, and in the refiner unit stage, the
softened chips of biomass are mechanically stripped apart in the
presence of the steam at greater than 70 PSI to make pulp.
4. The integrated plant of claim 1, where the two or more stages of
the Thermo Mechanical Pulping unit include a thermally decomposing
stage and a refiner unit stage, where the thermally decomposing
stage has the input cavity to receive chips of the biomass and a
low-pressure steam supply input applies steam into a vessel
containing the chips of biomass at an elevated temperature of 100
to 150 degrees C. at a pressure around atmospheric for a set period
of time, where chips of biomass with softened lignin are then fed
from the thermally decomposing stage to the refiner unit stage with
its higher pressure to further separate the cellulose fibers of the
biomass; and where in the refiner unit stage of the Thermo
Mechanical Pulping unit, the pressure and temperature are raised in
a chamber containing the chips of biomass with softened lignin to
an increased temperature of at least twenty degrees greater than an
operating environment of the vessel with chips of biomass in the
thermally decomposing stage and to an increased pressure greater
than three times atmospheric in the chamber but for a shorter
duration than the set period of time in the thermally decomposing
stage, where internally in the refiner unit stage, mechanical
pulping mechanisms apply mechanical force to assist the higher
pressure steam in physically tearing the cellulose fibers one from
another while the heat and pressure of the steam expands and blows
apart the structure of the lignin, fiber, and hemi-cellulose.
5. The integrated plant of claim 2, where a collection chamber at
an outlet stage of the refiner unit stage is used to collect the
biomass reduced into smaller particle sizes and in pulp form, which
should be more easily and rapidly gasified, where the produced
particles of biomass in pulp form includes fibers in the form of
long tubular strings of material that are torn, shredded and any
combination of the two, where the biomass particles separated into
fibers are preferred for the rapid biomass gasification reaction in
the reactor of the biomass gasifier because they create a higher
surface to volume ratio for the same amount of biomass compared to
chips of biomass, which allows higher heat transfer to the biomass
material and a more rapid thermal decomposition and gasification of
all the molecules in the biomass.
6. The integrated plant of claim 2, where the refiner unit stage
has a knife stage in the fiber separation unit that initially chops
the fibers of the biomass to 1-3 mm in lengths and then a high
pressure steam fiber separation stage furthers blowing apart of the
loosely grouped fibers in the chips of biomass, where the refiner
unit stage produces fiber particles that on average have an
equivalent spherical diameter of less than 3 mm.
7. The integrated plant of claim 2, where the multiple stages of
Thermo Mechanical Pulping are configured to loosen and strip fibers
from the lignin in the biomass, where a conveying system coupled to
a collection chamber at an outlet stage of the refiner unit stage
supplies particles of biomass in pulp form, where a majority of the
initial lignin and cellulose making up the biomass received in the
receiver section of the thermally decomposing stage remains in the
produced particles of biomass but now substantially separated from
the fibers in pulp form in the collection chamber at the outlet
stage of the refiner unit stage.
8. The integrated plant of claim 2, further comprising a chipper
unit, where a thermally decomposing stage and a refiner unit stage
of the Thermo Mechanical Pulping unit are configured to receive and
process chips of wood, bark leaves, and needles from the chipper
unit and the refiner unit stage turns them into pulp and feeds the
pulp subsequently as biomass particles into the biomass gasifier to
be turned into syngas components in a rapid biomass gasification
reaction, less than 5 seconds, to be used as the biomass to be
turned into syngas components.
9. The integrated plant of claim 2, where a collection chamber at
an outlet stage of the refiner unit stage is used to collect the
biomass reduced into smaller particle sizes and in pulp form, and a
conveyor system supplies the biomass in pulp form to a
torrefication unit to pyrolyze biomass at a temperature of less
than 700 degrees C. for a preset amount of time to create off gases
to be used in a creation of a portion of the syngas components
which are collected by a tank and eventually fed to the methanol
synthesis reactor.
10. The integrated plant of claim 1, further comprising: a water
separation unit, where a collection chamber at an outlet stage of
the refiner unit stage is used to collect the biomass reduced into
smaller particle sizes and in pulp form and is fed to the water
separation unit where water is removed from the pulp in a cyclone
unit and the reduced moisture content pulp made of loose fibers and
separated lignin and cellulose is fed by a conveying system to a
torrefaction unit to under go torrefaction to pyrolyze biomass at a
temperature of less than 700 degrees C. for a preset amount of
time; and where condensable hydrocarbons are separated by a filter
unit from the water removed from the pulp and then the condensable
hydrocarbons are sent to a gasoline blending unit, where the
gasoline blending unit is configured to blend gasoline produced
from a methanol to gasoline (MTG) reactor, which receives its
methanol derived from the syngas components in a proper ratio fed
to the methanol synthesis reactor, where the gasoline blending unit
is configured to blend the gasoline from the methanol to gasoline
reactor with condensable volatile materials including C5+
hydrocarbons collected during the pyrolyzation of the biomass in
the torrefication unit and those separated by the filter unit.
11. The integrated plant of claim 2, where the refiner unit stage
has a collection chamber to collect the biomass particles with
separated fiber and feed them to a feeding system for the biomass
gasifier, where the TMP unit is configured to receive two or more
types of biomass feed stocks, where the different types of biomass
include 1) soft woods, 2) hard woods, 3) grasses, 4) plant hulls,
and 5) any combination that are blended and thermo mechanically
processed into a homogenized torrefied feedstock within the TMP
unit that is subsequently collected and then fed into the biomass
gasifier, where the torrefaction unit assists in making a biomass
feed system that is feedstock flexible without changing out the
physical design of the feed supply equipment or the physical design
of the biomass gasifier via at least particle size control of the
biomass particles produced from refiner unit stage.
12. The integrated plant of claim 1, where the biomass gasifier has
a radiant heat transfer to particles flowing through the reactor
design with a rapid gasification residence time, of the biomass
particles of 0.1 to 5 seconds and preferably less one second, of
biomass particles and reactant gas flowing through the radiant heat
reactor, and primarily radiant heat from the surfaces of the
radiant heat reactor and particles entrained in the flow heat the
particles and resulting gases to a temperature in excess of
generally 900 degrees C. and preferably 1300.degree. C. to produce
the syngas components including carbon monoxide and hydrogen, as
well as keep produced methane at a level of .ltoreq.1% of the
compositional makeup of exit products, minimal tars remaining in
the exit products, and resulting ash, where the biomass particles
separated into fibers used as a feed stock into the radiant heat
reactor design conveys the beneficial effects of more effective
heat transfer of radiation to the biomass particles and increased
gasifier yield of generation of syngas components of carbon
monoxide and hydrogen for a given amount of biomass fed in, and
improved process hygiene via decreased production of tars and
C.sub.2+ olefins compared to chips of biomass, where a control
system for the radiant heat reactor matches the radiant heat
transferred from the surfaces of the reactor to a flow rate of the
biomass particles to produce the above benefits.
13. A method to generate syngas from biomass in an integrated
plant, comprising: receiving biomass as a feedstock in a Thermo
Mechanical Pulping process that has multiple stages; pre-treating
the biomass in the Thermo Mechanical Pulping process for subsequent
supply to a biomass gasifier; using a combination of heat,
pressure, moisture, and mechanical agitation that are applied to
the biomass to make the biomass into a pulp form in the multiple
stages, where the thermo chemical pulping process breaks down a
bulk structure of the received biomass, at least in part, by
applying steam to degrade bonds between lignin and hemi-cellulose
from cellulose fibers of the biomass; and reacting particles of the
biomass, broken down by the multiple stages of the Thermo
Mechanical Pulping unit, in the biomass gasifier in the presence of
steam in a rapid biomass gasification reaction at a temperature of
greater than 700 degrees C. in less than a five second residence
time in the biomass gasifier to create syngas components, including
hydrogen (H2) and carbon monoxide (CO), which are fed to a methanol
(CH3OH) synthesis process, where the Thermo Mechanical Pulping
process, biomass gasifier, and methanol (CH3OH) synthesis process
are part of an integrated plant.
14. The method to generate syngas of claim 13, where the multiple
stages of the Thermo Mechanical Pulping unit include a steam tube
stage and a refiner unit stage, where the steam tube stage has the
input cavity to receive chips of the biomass and a steam supply
input to apply steam into a vessel containing the chips of biomass
at an elevated temperature of 130 to 200 degrees C. at a pressure
between 70 and 110 PSI, where chips of biomass with softened lignin
are then fed from the steam tube stage to the refiner unit stage at
the same pressure as the steam tube stage where a mechanical
separator is configured to further to cooperate with the steam to
separate cellulose fibers of the biomass into 1) three or more
individual bundles of fibers, 2) individual strands of fibers, and
3) any combination of both.
15. The method to generate syngas of claim 13, further comprising:
performing the Thermo Mechanical Pulping processing in a multiple
stage TMP unit, where chips of the biomass are received and
low-pressure steam is applied to the chips of biomass at an
elevated temperature of 100 to 150 degrees C. at a pressure around
atmospheric for a set period of time in a thermally decomposing
stage, and where chips of biomass with softened lignin are then fed
from the thermally decomposing stage to the refiner unit stage with
its higher pressure to further separate the cellulose fibers of the
biomass; and. raising pressure and temperature in the refiner unit
stage of the Thermo Mechanical Pulping unit on the chips of biomass
with softened lignin to an increased temperature of at least twenty
degrees greater than an operating environment of the chips of
biomass in the thermally decomposing stage and to an increased
pressure greater than three times atmospheric but for a shorter
duration than the set period of time in the thermally decomposing
stage, and applying mechanical force to assist the higher pressure
steam in physically tearing the cellulose fibers one from another
while the heat and pressure of the steam expands and blows apart
the structure of the lignin, fiber and hemi-cellulose.
16. The method to generate syngas of claim 14, further comprising:
collecting the biomass reduced into smaller particle sizes and in
pulp form, which should be more easily and rapidly gasified, in an
outlet stage of the refiner unit stage where the produced particles
of biomass in pulp form includes fibers in the form of long tubular
strings of material that are torn, shredded and any combination of
the two; and using the biomass particles separated into fibers in
the rapid biomass gasification reaction in the reactor of the
biomass gasifier because they create a higher surface to volume
ratio for the same amount of biomass compared to chips of biomass,
which allows higher heat transfer to the biomass material and a
more rapid thermal decomposition and gasification of all the
molecules in the biomass.
17. The method to generate syngas of claim 14, further comprising:
loosening and stripping the fibers from the lignin in the biomass
in the multiple stages of the Thermo Mechanical Pulping, but
retaining and feeding a majority of the initial lignin and
cellulose making up the biomass received in thermally decomposing
stage as the particles of biomass used in the rapid biomass
gasification reaction.
18. The method to generate syngas of claim 13, further comprising:
using woody biomass and at least a portion of its leaves, needles,
and bark as feedstock into the Thermo Mechanical Pulping process to
be turned into pulp and fed subsequently as biomass particles into
the biomass gasifier to be turned into syngas components in a rapid
biomass gasification reaction.
19. The method to generate syngas of claim 14, further comprising:
collecting the biomass reduced into smaller particle sizes and in
pulp form in the refiner unit stage; supplying the biomass in pulp
form to a torrefication unit to pyrolyze biomass at a temperature
of less than 700 degrees C. for a preset amount of time to create
off gases to be used in a creation of a portion of the syngas
components which are collected by a tank and eventually fed to the
methanol synthesis reactor; and using a catalytic conversion
process on the collected off gases from the tank to create the
portion of the syngas components.
20. The method to generate syngas of claim 14, where the refiner
unit stage has a collection chamber to collect the biomass
particles with separated fiber and feed them to a feeding system
for the biomass gasifier, where the TMP unit is configured to
receive two or more types of biomass feed stocks, where the
different types of biomass include 1) soft woods, 2) hard woods, 3)
grasses, 4) plant hulls, and 5) any combination that are blended
and thermo mechanically processed into a homogenized torrefied
feedstock within the TMP unit that is subsequently collected and
then fed into the biomass gasifier, where the torrefaction unit
assists in making a biomass feed system that is feedstock flexible
without changing out the physical design of the feed supply
equipment or the physical design of the biomass gasifier via at
least particle size control of the biomass particles produced from
refiner unit stage.
Description
FIELD
[0001] The invention generally relates to pre-treatment of biomass
using thermo mechanical methods before gasification and in an
embodiment specifically to an integrated plant that uses this
biomass to produce a liquid fuel from the biomass.
BACKGROUND
[0002] Prior to the emergence of the petrochemical industry, wood
distillation was the primary source of industrially important
organic chemicals, but most wood distillation plants were closed by
1950. A resurgence in interest in wood distillation products arose
in the late 1900's, as efforts were focused on renewable energy
sources as an alternative to petroleum (Gade 2010). Much of this
renewed interest has been in the use of fast pyrolysis to produce
bio-oil, or "bio-crude." In this process, biomass of small particle
size is rapidly heated (1-2 sec), at high temperature (500.degree.
C.), and the vapor is rapidly cooled, to yield .about.70% liquid
bio-oil. The bio-oil is an acidic, highly oxygenated, product that
is subject to aging and must be further refined to produce
satisfactory liquid fuels. To date, no large-scale
commercialization of bio-oil or other integrated plant to
economically make bio-fuel has been achieved.
SUMMARY
[0003] In an embodiment, an integrated plant generates syngas from
biomass where the integrated plant includes a Thermo Mechanical
Pulping process, a biomass gasifier, a methanol synthesis process,
and a liquid fuel generation process. Biomass is received as a
feedstock in the Thermo Mechanical Pulping process. The biomass is
pre-treated in the Thermo Mechanical Pulping process for subsequent
supply to a biomass gasifier by using a combination of heat,
pressure, moisture, and mechanical agitation that are applied to
the biomass to make the biomass into a pulp form. The thermo
mechanical pulping process breaks down a bulk structure of the
received biomass, at least in part, by applying steam to degrade
bonds between the lignin and the hemi-cellulose from cellulose
fibers of the biomass. Next, the broken down particles of the
biomass are reacted in a rapid biomass gasification reaction at a
temperature of greater than 700 degrees C. to create syngas
components, which are fed to a methanol synthesis process. The
methanol may be used to produce a number of liquid fuels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The multiple drawings refer to the example embodiments of
the invention.
[0005] FIG. 1 illustrates a flow schematic of an embodiment of a
Thermo Mechanical Pulping unit having an input cavity to receive
biomass as a feedstock, a steam supply input, and two or more
stages to pre-treat the biomass for subsequent supply to a biomass
gasifier.
[0006] FIG. 2 illustrates a flow schematic of an embodiment of a
Thermo Mechanical Pulping unit having a refiner unit stage that
supplies particles of biomass in pulp form to either a torrefaction
unit, or to the biomass gasifier, or to a catalytic converter.
[0007] FIG. 3 illustrates an embodiment of a flow diagram of an
integrated plant to generate syngas from biomass and generate a
liquid fuel product from the syngas.
[0008] FIG. 4 illustrates a table of volatiles produced in an
example torrefaction unit and/or TMP unit that are segregated into
two or more operational stages.
[0009] FIG. 5 illustrates a flow schematic of an embodiment for the
radiant heat chemical reactor configured to generate chemical
products including synthesis gas products.
[0010] While the invention is subject to various modifications and
alternative forms, specific embodiments thereof have been shown by
way of example in the drawings and will herein be described in
detail. The invention should be understood to not be limited to the
particular forms disclosed, but on the contrary, the intention is
to cover all modifications, equivalents, and alternatives falling
within the spirit and scope of the invention.
DETAILED DISCUSSION
[0011] In the following description, numerous specific details are
set forth, such as examples of specific chemicals, named
components, connections, types of heat sources, etc., in order to
provide a thorough understanding of the present invention. It will
be apparent, however, to one skilled in the art that the present
invention may be practiced without these specific details. In other
instances, well known components or methods have not been described
in detail but rather in a block diagram in order to avoid
unnecessarily obscuring the present invention. Thus, the specific
details set forth are merely exemplary. The specific details may be
varied from and still be contemplated to be within the spirit and
scope of the present invention.
[0012] In general, a number of example processes for and
apparatuses associated with a pre-treatments of biomass are
described. The following drawings and text describe various example
implementations for an integrated plant using the pre-treatments of
biomass. In an embodiment, the integrated plant contains a Thermo
Mechanical Pulping unit and a biomass gasifier to generate syngas
from biomass. The Thermo Mechanical Pulping unit at least has an
input cavity to receive biomass as a feedstock, a steam supply
input, and two or more stages to pre-treat the biomass for
subsequent supply to a biomass gasifier. The two or more stages use
any combination of heat, pressure, moisture, and mechanical
agitation that are applied to the biomass to make the biomass into
a pulp form. The Thermo Mechanical Pulping process breaks down the
bulk structure of the biomass, at least in part, by applying steam
from the steam supply input and potentially mechanical force to
soften and degrade bonds between the lignin and the hemi-cellulose
from cellulose fibers of the biomass. The biomass gasifier has at
least a reactor configured to react particles of the biomass broken
down by the two or more stages of the Thermo Mechanical Pulping
unit and those biomass particles are subsequently fed to a feed
section of the biomass gasifier. A possible biomass gasifier
implementation has a high temperature steam supply input and one or
more regenerative heaters. In the presence of the steam, the
particles of the biomass broken down by the Thermo Mechanical
Pulping unit are reacted in the reactor vessel in a rapid biomass
gasification reaction at a temperature of greater than 700 degrees
C. in less than a five second residence time in the biomass
gasifier to create syngas components, including hydrogen (H2) and
carbon monoxide (CO), which are fed to a methanol (CH3OH) synthesis
reactor.
[0013] In an embodiment, steam is applied to biomass at a
temperature above a glass transition point of the lignin to soften
the lignin so the cellulose fibers of the biomass can easily be
mechanically stripped apart from the biomass in chip mass form.
This temperature of the glass transition point of the lignin is
generally above 150.degree. C. for dry chips of biomass. These
temperatures can be lower in the presence of water. The TMP process
may be a two or more stage process similar in some aspects to the
one used to make medium density fiber board (MDF). In the first
stage, the TMP process uses whole chips of biomass including
leaves, needles, bark, and wood. The chips of biomass are heated to
about 160.degree. C. using the steam at about 90 psi (6.2 bar) for
about 120 seconds. No additional moisture is added to the chips of
biomass beyond the steam condensate and pump seal water that may be
used as a process aid in the process. In the second stage, the
softened chips of biomass are sent directly to a refiner unit to
mechanically strip apart the biomass and make pulp using refining
energy in the range of less than about 300 to 100 kwh/odmt
(kilowatt hours/oven dry metric ton) and preferably energy less
than 100 kwh/odmt. One skilled in the art will understand parts and
aspects of many of the designs discussed below within this
illustrative document may be used as stand-alone concepts or in
combination with each other.
[0014] FIG. 1 illustrates a flow schematic of an embodiment of a
Thermo Mechanical Pulping unit having an input cavity to receive
biomass as a feedstock, a steam supply input, and two or more
stages to pre-treat the biomass for subsequent supply to a biomass
gasifier.
[0015] A pre-treatment of biomass occurs using a thermo mechanical
method before the gasification of the biomass in the biomass
gasifier. Thermo Mechanical Pulping, also known as TMP, is one such
thermo mechanical method that can be used where the pulp is
produced by processing wood chips using heat (thus thermo) and a
mechanical refining movement (thus mechanical). The Thermo
Mechanical Pulping unit may be a multiple stage process.
[0016] Prior to the TMP, the logs of trees may first be stripped of
their bark into a debarker unit 102 and then converted into small
chips by a chipper unit 104. An on-site or off-site mill uses wood
(trees) as the biomass fiber source and removes the bark. Removal
of the bark is done in the debarker unit 102. Bark contains
relatively few usable fibers for paper production because it
darkens the pulp. In the gasification process in an embodiment, the
debarker unit 102 removes the bark from the biomass and feeds all
or just portions of the removed bark as well as leaves, needles and
other carbon organics to the Thermo Mechanical Pulping unit to be
turned into pulp and fed subsequently as biomass particles into the
biomass gasifier to be turned into syngas components in a rapid
biomass gasification reaction. In the alternative, the plant just
feeds all of the biomass directly into the chipper 104 and thus has
no need for a debarker unit 102. Thus, the thermally decomposing
stage 106 and the refiner unit stage 108 can be configured to
receive and process all or just portions of the removed bark as
well as leaves, needles and other carbon organics to be used as the
biomass to be turned into syngas components. Note if any bark is
removed, then the bark may also be segregated and burned, along
with other unusable plant material, as the fuel source for a
traditional wood burning boiler to generate steam for use in the
TMP stages, and/or in the biomass gasifier 114.
[0017] As discussed, the logs of wood potentially other biomass of
needles, bark, leaves, etc., are chipped before being processed
further to loosen and free the fibers in the biomass. The biomass
chipper unit 104 has shearing tools to chip the logs of wood and
other plant parts used as biomass feedstock and cooperating screens
to provide some uniformity to the size of the chips of biomass.
Woody biomass arrives at the later TMP pulping stages in the form
of chips that can range in average size from 0.5 to 3'' in length
and a tight consistency in length and diameter is not required for
the feed stock chips. It is relatively easy and energy efficient to
create chips with this size before pulping and subsequent
gasification.
[0018] The wood may also be steamed prior to the grinding/shearing
to the make chips. These chips may have a large moisture content
and will be thermally heated from the steam and then a mechanical
force is applied to the wood chips in a shearing or grinding
action, which generates additional heat and water vapor that
softens the lignin, which aids in separating the individual fibers
of the wood in the later stages. The soften structure of the woody
biomass can be easier to chip.
[0019] The next step is the Thermo Mechanical Pulping processing,
where heat, pressure, moisture, and mechanical force are applied to
the fibrous chips of biomass to make pulp.
[0020] The pulp may be a lignocellulosic fibrous material prepared
by chemically and/or mechanically separating cellulose fibers from
wood, fiber crops, or waste paper. Wood pulp comes from softwood
trees, such as spruce, pine, fir, larch and hemlock, and hardwood
trees, such as eucalyptus, aspen and birch. Wood and other plant
materials used to make pulp contain three main components (apart
from water): cellulose fibers (used in other technologies for paper
making), lignin (a three-dimensional polymer that binds the
cellulose fibers together, which is chemically removed in the paper
making field) and hemi-celluloses, (shorter branched carbohydrate
polymers). The biomass contains cellulose fibers and hemi-cellulose
that are held together with lignin. The aim of pulping is to break
down the bulk structure of the fiber source, be it chip form, stem
form, or other plant parts, into the small groups of fibers or even
into individual constituent fibers.
[0021] The multiple stages in the Thermo Mechanical Pulping unit at
least include a thermally decomposing stage 106 and a refiner unit
stage 108. The Thermo Mechanical Pulping unit has an input cavity
to receive biomass as a feedstock, a steam supply input, and two or
more stages to pre-treat the biomass for subsequent supply to a
biomass gasifier 114. The stages use a combination of heat,
pressure, moisture, and mechanical agitation that are applied to
the biomass to make the biomass into a pulp form. The thermo
mechanical pulping process breaks down a bulk structure of the
received biomass, at least in part, by applying steam from the
steam supply input to soften the lignin and make it easier to
degrade bonds between the lignin and the hemi-cellulose from
cellulose fibers of the biomass.
[0022] Strength of the fibers is further impaired with the
gasification's use of thermo mechanical pulping because the fibers
are separated to potentially individual fibers and also cut to
small dimensions. A lack of concern exists to maintain the strength
of the fibers in the woody biomass chips compared to the paper
pulping industry. The traditional TMP process tries to maintain the
strength of the fibers to make particle board, newspapers, etc. In
the current application of using the fibrous biomass in pulp form
as a chemical reactant feedstock, the steam in connection with the
mechanical force can be used to weaken the fibers and the fibers
can then be cut to small dimensions because the fibers, lignin, and
cellulose will eventually be thermally decomposed into syngas
components. This process of TMP for gasification is less costly
than producing paper with TMP because the gasification process does
not require full length strong fibers as required for making paper
or the traditional extra steps used to keep the strength of the
fibers.
[0023] The Thermo Mechanical Pulping process also reduces the
amount of energy required to produce particles of biomass compared
to mechanical treatment alone. A major issue in the paper industry
is that mechanical pulp mills use large amounts of energy, mostly
electricity to power motors that turn the grinders. Steam treatment
significantly reduces the total energy needed to make the pulp and
eases the separation of the fibers. Thus, many advantages exist to
the gasification of woody and other fibrous biomass to strip apart
the fibers from the lignin.
[0024] The steam tube stage 106 has the input cavity to receive
chips of the biomass. The steam tube stage 106 has a steam supply
input applies steam into a vessel containing the chips of biomass
at an elevated temperature of 100 to 200 degrees C., and preferably
about 165 degrees C., at a pressure above atmospheric, such as
around 90 psi, for a short period of time, such as approximately 2
minutes. The chips of biomass with the softened lignin are then fed
from the steam tube stage 106 to the refiner unit stage 108 to
further separate the fibers.
[0025] In the refiner unit stage 108 of the Thermo Mechanical
Pulping unit, it is operated at the same pressure and temperature
as the steam tube stage. Internally in the refiner unit stage 108,
mechanical pulping mechanisms apply mechanical force to assist the
steam in physically tearing the cellulose fibers one from another
while the heat and pressure of the steam expands and blows apart
the structure of the lignin, fiber and cellulose.
[0026] There are a number of different mechanical processes that
can be used to separate the wood fibers. For example, manufactured
grindstones with embedded silicon carbide or aluminum oxide or
metal discs called refiner plates can be used to grind the biomass
chips. Thus, the chips are steamed while being refined by the
grindstones or metal discs to create the pulp. These chips of
biomass have a large moisture content, are thermally heated from
the steam, expanded by the elevated temperature and pressure, and
then a mechanical force may also be applied to the wood chips in a
crushing, shearing, vibrating, or grinding action, which generates
additional heat and shredding action, which aids in separating the
individual fibers from each other and the lignin.
[0027] The TMP unit reduces the biomass into smaller particle sizes
that should be more easily and rapidly gasified. Fibers are long
tubular strings of material, whereas chips are irregular spheres.
The fibers compare to angel hair spaghetti, whereas chips are more
like ravioli. Torn and shredded fibers may be preferred for the
gasification process because they create a higher surface to volume
ratio for the same amount of biomass. The higher surface area of
the fibers traveling through the biomass gasifier 114 compared to a
chip allows higher heat transfer to the biomass material and a more
rapid thermal decomposition and gasification of all the molecules
in the biomass. Thus, nearly all of the biomass material lignin,
fiber, and cellulose completely gasify rather than some of the
inner portions of the chip not decomposing to the same extent to
that the crusted shell of a char chip decomposes.
[0028] A collection chamber at an outlet stage of the refiner unit
stage 108 is used to collect the biomass reduced into smaller
particle sizes and in pulp form, which should be more easily and
rapidly gasified. The produced particles of biomass in pulp form
include fibers in the form of long tubular strings of material that
are torn and/or shredded. The biomass particles separated into
fibers are preferred for the biomass gasification reaction in the
biomass gasifier 114 because they create a higher surface to volume
ratio for the same amount of biomass compared to chips of biomass,
which allows higher heat transfer to the biomass material and a
more rapid thermal decomposition and gasification of all the
molecules in the biomass. The refiner unit stage 108 has a knife
stage in the fiber separation unit that initially separates the
fibers from the chips and may chop the fibers of the biomass to
shorter lengths of 1-3 mm and then a high pressure steam fiber
separation stage furthers the blowing apart of the loosely grouped
fibers in the particles of biomass. The refiner unit produces fiber
particles that on average are approximately 20-50 .mu.m thick and
1-3 mm in length. In another embodiment, the fibers may have an
equivalent spherical diameter of less than 3 mm.
[0029] In another embodiment, the Thermo Mechanical Pulping unit
has a low-pressure steam supply input in a first stage and a high
pressure steam supply in a second stage to pretreat the biomass for
subsequent supply to a biomass gasifier. The multiple stages in the
Thermo Mechanical Pulping unit at least include a first thermally
decomposing stage 106 and a second refiner unit stage 108. The
thermo mechanical pulping process breaks down a bulk structure of
the received biomass, at least in part, by applying steam from the
low-pressure steam supply input to degrade bonds between the lignin
and the hemi-cellulose from cellulose fibers of the biomass. The
thermally decomposing stage 106 has a low-pressure steam supply
input applies steam into a vessel containing the chips of biomass
at an elevated temperature of 100 to 150 degrees C., and preferably
about 130 degrees C., at a pressure around atmospheric (15 psi) for
a set period of time, such as approximately 10-30 minutes. The
softened biomass may be then screened and cleaned. The chips of
biomass with the softened lignin are then fed from the thermally
decomposing stage 106 to the refiner unit stage 108 with its higher
pressure to further separate the fibers.
[0030] In the second refiner unit stage 108 of the Thermo
Mechanical Pulping unit, the pressure and temperature are raised in
a chamber containing the chips of biomass with softened lignin to
an increased temperature of at least twenty degrees, such as 150 C,
greater than an operating environment of the vessel with chips of
biomass in the thermally decomposing stage 106, and to an increased
pressure greater than three times atmospheric in the chamber, such
as 60 pounds per square inch (psi), but for a shorter duration than
the set period of time in the thermally decomposing stage 106, such
as less than 5 minutes. Internally in the refiner unit stage 108,
mechanical pulping mechanisms apply mechanical force to assist the
higher pressure steam in physically tearing the cellulose fibers
one from another while the heat and pressure of the steam expands
and blows apart the structure of the lignin, fiber and
cellulose.
[0031] FIG. 2 illustrates a flow schematic of an embodiment of a
Thermo Mechanical Pulping unit having a refiner unit stage that
supplies particles of biomass in pulp form to either a torrefaction
unit, or to the biomass gasifier, or to a catalytic converter.
[0032] Overall, the Thermo Mechanical Pulping loosens and strips
the fibers from the lignin. A conveying system coupled to a
collection chamber at the outlet stage of the refiner unit stage
208 supplies particles of biomass in pulp form to either a
torrefaction unit 212, or to the biomass gasifier 214, or to a
catalytic converter 215. A majority of the initial lignin and
cellulose making up the biomass in the receiver section of the
steam tube stage in the TMP unit 208 remains in the produced
particles of biomass but now substantially separated from the
fibers in pulp form in the collection chamber at the outlet stage
of the refiner unit stage 208.
[0033] In an embodiment, the collection chamber at an outlet stage
of the refiner unit stage 208 is used to collect the biomass
reduced into smaller particle sizes and in pulp form, and a
conveyor system supplies the biomass in pulp form to a
torrefication unit 212 to pyrolyze biomass at a temperature of less
than 700 degrees C. for a preset amount of time to create off gases
to be used in a creation of a portion of the syngas components,
which are collected by a collection chamber and eventually fed to
the methanol synthesis reactor. The collection chamber in the TMP
unit 208 is configured to collect non-condensable hydrocarbons from
any off gases produced from the biomass during the TMP process.
[0034] After the refiner unit stage 208, water is removed from the
pulp in a water separation unit 211, for example a cyclone unit,
and the reduced moisture content pulp made of loose fibers and
separated lignin and cellulose may be fed to a torrefaction unit
212 to under go multiple stages of torrefaction. Condensable
hydrocarbons including alcohols, ethers, and other C5 hydrocarbons
may be separated by a filter unit 213 from the water removed from
the pulp and then the condensable hydrocarbons are sent to a
gasoline blending unit
[0035] FIG. 3 illustrates an embodiment of a flow diagram of an
integrated plant to generate syngas from biomass and generate a
liquid fuel product from the syngas.
[0036] As discussed, the condensable hydrocarbons separated by the
filter unit from the water removed from the pulp may be sent to a
gasoline blending unit 318. The gasoline blending unit 318 is
configured to blend gasoline produced from a methanol to gasoline
(MTG) reactor 320, which receives its methanol derived from the
syngas components in a proper ratio fed to the methanol synthesis
reactor 310 from the biomass gasifier 314, the catalytic converter
316, and H2 and CO ballast tanks. The gasoline blending unit 318 is
configured to blend the gasoline from the methanol to gasoline
reactor 320 with condensable volatile materials including C5+
hydrocarbons collected during the pyrolyzation of the biomass in
the torrefication unit 312 and those separated by the filter unit,
which removes water from the pulp produced in the TMP unit 308.
[0037] One or more gas collection tanks in the TMP unit 308 may
collect non-condensable hydrocarbons from any off gases produced
from the biomass during the TMP process and send those
non-condensable hydrocarbons with any collected in the
torrefication unit 312 to a catalytic converter 316.
[0038] In another embodiment, the reduced moisture content pulp may
go directly from TMP unit 308 to the biomass gasifier 314, a
torrefaction unit 312, or to a catalytic converter 316. Generally,
the pulp goes to the torrefaction unit 312 and then onto the
biomass gasifier 314.
[0039] The refiner unit stage in the TMP unit 308 has a collection
chamber to collect the biomass particles with separated fiber and
feeds them to a feeding system for the biomass gasifier 314. The
TMP unit 308 is configured to receive two or more types of biomass
feed stocks, where the different types of biomass include 1) soft
woods, 2) hard woods, 3) grasses, 4) plant hulls, and 5) any
combination that are blended and thermo mechanically processed into
a homogenized torrefied feedstock within the TMP unit 308 that is
subsequently collected and then fed into the biomass gasifier 314.
The torrefaction unit 312 assists in making a biomass feed system
that is feedstock flexible without changing out the physical design
of the feed supply equipment or the physical design of the biomass
gasifier via at least particle size control of the biomass
particles produced from refiner unit stage 308. The general
compositions of biomass types that can be blended, for example,
include:
TABLE-US-00001 Component Wood Non-wood Cellulose 40-45% 30-45% Hemi
cellulose 23-35% 20-35% Lignin 20-30% 10-25%
[0040] The biomass gasifier 314 has a reactor configured to react
particles of the biomass broken down by the two or more stages of
the Thermo Mechanical Pulping unit and those biomass particles are
subsequently fed to a feed section of the biomass gasifier 314. The
biomass gasifier 314 has a high temperature steam supply input and
one or more regenerative heaters, and in the presence of the steam
the particles of the biomass broken down by the Thermo Mechanical
Pulping unit are reacted in the reactor vessel in a rapid biomass
gasification reaction at a temperature of greater than 700 degrees
C. in less than a five second residence time in the biomass
gasifier 314 to create syngas components, including hydrogen (H2)
and carbon monoxide (CO), which are fed to a methanol (CH3OH)
synthesis reactor 310. In the gasifier, the heat transferred to the
biomass particles made of loose cellulose fibers, lignin, and
hemicellulose no longer needs to penetrate the layers of lignin and
hemicellulose to reach the fibers. Alternatively, even if some
lignin and hemicellulose remains on the fibers making larger fiber
bundles, the high temperature and pressure inside the biomass
gasifier 314 more easily expands and blows apart the bonds of the
structurally weaker component parts of the biomass. In some
embodiments, the rapid biomass gasification reaction occurs at a
temperature of greater than 1000 degrees C. to ensure the removal
tars from forming during the gasification reaction. However, due to
the TMP action, formation of tars during biomass gasification can
occur on a consistent basis as low as at the 700 degree C.
temperature. Thus, a starting temperature of 700 degrees but less
than 950 degrees is potentially a significant range of operation
for the biomass gasifier. All of the biomass gasifies more
thoroughly and readily. The TMP pre-treatment to the woody biomass
improves the biomass gasifier reactor performance of syngas
components yield and less tars while maintaining substantially all
of the original carbon content contained in the biomass.
[0041] The biomass gasifier 314 may have a radiant heat transfer to
particles flowing through the reactor design with a rapid
gasification residence time, of the biomass particles of 0.1 to 5
seconds and preferably less one second, of biomass particles and
reactant gas flowing through the radiant heat reactor, and
primarily radiant heat from the surfaces of the radiant heat
reactor and particles entrained in the flow heat the particles and
resulting gases to a temperature in excess of generally 700 degrees
C. and preferably 1300.degree. C. to produce the syngas components
including carbon monoxide and hydrogen, as well as keep produced
methane at a level of .ltoreq.1% of the compositional makeup of
exit products, minimal tars remaining in the exit products, and
resulting ash. In some embodiments, the temperature range for
biomass gasification is greater than 800 degrees C. to 1400 degrees
C. In some embodiments, the temperature range for biomass
gasification is greater than 900 degrees C. to 1450 degrees C. In
some embodiments, the temperature range for biomass gasification is
greater than 1000 degrees C. In some embodiments, the temperature
range for biomass gasification is greater than 700 degrees C. The
biomass particles separated into fibers and used as a feed stock
into the radiant heat reactor conveys the beneficial effects of
more effective heat transfer of radiation to the biomass particles
and increased gasifier yield of generation of syngas components of
carbon monoxide and hydrogen for a given amount of biomass fed in,
and improved process hygiene via decreased production of tars and
C2+ olefins compared to chips of biomass. A control system for the
radiant heat reactor 314 matches the radiant heat transferred from
the surfaces of the reactor to a flow rate of the biomass particles
to produce the above benefits.
[0042] The cellulose fibers, lignin, and hemicellulose produced
from the TMP unit can be further processed using torrefaction
and/or extractive removal, followed by biomass gasification at
temperatures greater than 900 degrees C. in a biomass gasifier
314.
[0043] Alternative ways exist to create the syngas. The biomass is
supplied to the Thermo-Mechanical Pulping unit 208, water is
removed from the pulp, and the pulp is exposed to steam and oxygen
and then supplied to a catalytic converter 215. The catalytic
converter 215 produces H2, CO, and Ash. A solids separator removes
the Ash from the gas stream. Synthesis gas of H2 and CO from the
gasifier and the catalytic converter 215 exit gases are sent to
methanol synthesis reactors.
[0044] Other methods of TMP may include chemithermomechanical
pulping, in which the wood chips can be pre-treated with sodium
carbonate, sodium hydroxide, and other chemicals prior to refining
with equipment similar to a mechanical mill. The conditions of the
chemical treatment are much less vigorous (lower temperature,
shorter time, less extreme pH) than in a chemical pulping process
since the goal is to make the fibers easier to refine, not to
remove lignin as in a fully chemical process.
[0045] Referring to FIG. 2, the plant uses any combination of the
three ways to generate syngas for methanol production. 1) The TMP
unit and/or torrefaction of biomass causes off gases to be fed to a
catalytic converter 216 that can generate hydrogen and carbon
monoxide for methanol production. 2) The biomass gasifier 214
gasifies biomass at high enough temperatures to eliminate a need
for a catalyst to generate hydrogen and carbon monoxide for
methanol production. 3) Alternatively, a lower temperature
catalytic conversion of particles of biomass may be used to
generate hydrogen and carbon monoxide for methanol production.
Similarly, the thermal mechanical pulping process and torrefaction
process may be used to generate condensable hydrocarbons for use in
gasoline blending to increase the octane of the final gasoline
product.
[0046] The torrefaction unit 212 pyrolyzes biomass from the TMP
unit 208 to create off gases to be used in a creation of a portion
of the syngas components fed to the methanol synthesis reactor and
a char remains to be supplied to the biomass gasifier 214. Syngas
may be a mixture of carbon monoxide and hydrogen that can be
converted into a large number of organic compounds that are useful
as chemical feed stocks, fuels and solvents.
[0047] The torrefaction unit 212 is configured to produce and
collect 1) condensable materials with significant fuel blending
value, 2) char, and 3) non-condensable gases including C1-4
olefins. The torrefaction unit 212 is configured to route the
separated products as follows 1) condensable materials with
significant fuel blending value are routed to the gasoline blending
unit, 2) char is routed as a feedstock for the biomass gasifier
214, which produces a portion of the syngas components, and 3)
non-condensable gases including C1-4 olefins are routed to a
catalytic reactor in parallel with biomass gasifier 214 in order to
create the other portion of the syngas component to be fed to the
methanol synthesis reactor 210.
[0048] Torrefaction may be a thermo chemical process used to
pre-treat biomass to increase the efficiency of combustion and
gasification processes. In this process, biomass is subjected to
temperatures of 200-700.degree. C. for ten to sixty minutes to
drive off volatile materials, leaving a highly friable solid char
material with increased energy density. During the low temperature
stages of this thermal decomposition of the biomass, the biomass
decomposes into volatile gases and solid char. Biomass is generally
made up of a significantly higher amount of volatile matter than
coal. For instance, up to 80 percent of the biomass can be volatile
matter compared to coal, which is up to 20%.
[0049] Note, olefins may be any unsaturated hydrocarbon, such as
ethylene, propylene, and butylenes, containing one or more pairs of
carbon atoms linked by a double bond. Olefins may have the general
formula CnH2n, C being a carbon atom, H a hydrogen atom, and n an
integer. The olefins are formed during the thermal decomposition
(breaking down of large molecules) of the biomass and are useful in
the generation of a liquid fuel such as gasoline. Non-condensable
olefins containing two to four carbon atoms per molecule (C2-C4)
are generally gaseous at ordinary temperatures and pressure;
whereas, condensable olefins generally contain five or more carbon
atoms (C5+) and are usually liquid at ordinary temperatures and
pressure. Cn usually denotes how many carbon molecules are making
up the hydrocarbon compound.
[0050] The torrefaction unit 212 has two or more areas to segregate
out and then route the non-condensable gases including the C1 to C4
olefins, as well as other gases including CO, CH4, CO2 and H2,
through a supply line to the catalytic converter 216 that
catalytically transform portions of the non-condensable gases to
the syngas components of CO, H2, CO2 in small amounts, and
potentially CH4 that are sent in parallel with the portion of
syngas components from the biomass gasifier 214 to a combined input
to the methanol synthesis reactor. The catalytic converter 216 has
a control system to regulate a supply of an oxygenated gas and
steam along with the non-condensable gases to the catalytic
converter 216, which produces at least H2, and CO as exit gases.
The catalytic converter 216 uses the control system and the
composition of a catalyst material inside the catalytic converter
216 to, rather than convert the supplied non-condensable gases
completely into CO2 and H2O in the exit gas, the non-condensable
gases, steam, and oxygenated gas are passed through the catalytic
converter 216 in a proper ratio to achieve an equilibrium reaction
that favors a production of carbon monoxide (CO) and hydrogen (H2)
in the exit gas; and thus, reclaim the valuable Renewable
Identification Number (RIN) credits associated with the
non-condensable gases. RIN credits are a numeric code that is
generated by the producer or importer of renewable fuel
representing gallons of renewable fuel produced using a renewable
energy crop, such as biomass. The primary negative of torrefaction
in prior suggestions is the loss of carbon and the associated RIN
credits in the volatile materials removed by torrefaction.
[0051] The one or more catalytic converters may use a catalytic
conversion process that oxidizes the incoming olefins as follows:
CnH2n+[3nO2+1O2]/2.fwdarw.xCO2+xCO+x+1H2O. For example, when the
control system rapidly alternates the air to C1 to C4
non-condensable gas input into the catalytic converter 216, then
the reaction runs heavy or lean of stoichiometry. By doing this the
carbon monoxide and oxygen present in the exhaust gas from the
converter alternates with the air to C1-C4 non-condensable ratio.
When the air to C1-C4 non-condensable ratio is richer than
stoichiometry, the carbon monoxide content of the exhaust gas rises
and the oxygen and carbon dioxide content falls. Catalyst materials
inside the converter 216, such as platinum/palladium/Rhodium/ and
Cerium, may be used to promote the equilibrium reaction that favors
a production of carbon monoxide (CO) and hydrogen (H2) in the exit
gas. The cerium may store and release oxygen during these
reactions. In the catalytic converter 216, the chemical catalyst
material is used but not consumed to augment the chemical
reaction.
[0052] The system is designed to remove the C1-C4 materials from
the volatile stream and then blend the remaining C5+ materials in
the stream directly into gasoline. This is beneficial to the
finished gasoline product to increase its octane rating as the
condensable blendable materials are largely olefins and branched
hydrocarbons (CnH2n+2), which typically have higher octane ratings.
There are some heavier materials, C25+, which may need to be
removed by the filters, depending on the actual quantities in
commercial production and type of biomass material being utilized
by the integrated plant. Gasoline may be a complex mixture of
potentially hundreds of different hydrocarbons. Most of the
hydrocarbons are saturated and contain 4 to 12 carbon atoms per
molecule.
[0053] Biomass gasification is used to decompose the complex
hydrocarbons of biomass into simpler gaseous molecules, primarily
hydrogen, carbon monoxide, and carbon dioxide. Some char, mineral
ash, and tars are also formed, along with methane, ethane, water,
and other constituents. The mixture of raw product gases vary
according to the types of biomass feedstock used and gasification
processes used. The product gas must be cleaned of solids, tars,
and other contaminants sufficient for the intended use.
[0054] A sulfur filter and other filters between the torrefaction
unit 212 and the catalytic converter 216 receive the
non-condensable gases collected and routed from the torrefaction
unit 212. The hydro treater sulfur filter and other filters are
configured to remove contaminants from the stream of
non-condensable gases that would inactivate or otherwise harm the
catalyst material within the catalytic converter 216. This may
include sulfur compounds (e.g. H2S, mercaptans), nitrogen compounds
(e.g. NH3, HCN), halides (e.g. HCL), and heavy organic compounds
that are known collectively as "tar". Next, depending on the
catalyst being used and the product being made, the ratio of
hydrogen to carbon monoxide may need to be adjusted and the carbon
dioxide byproduct may also need to be removed.
[0055] Referring to FIG. 3, the biomass gasifier has a gas clean up
section to clean ash, sulfur, water, and other contaminants from
the syngas gas stream exiting the biomass gasifier 314. The syngas
is then compressed to the proper pressure needed for methanol
synthesis. The syngas from the catalytic converter 316 may connect
upstream or downstream of the compression stage.
[0056] The synthesis gas of H2 and CO from the gasifier and the
catalytic converter 316 exit gases are sent to the common input to
the one or more methanol synthesis reactors. In addition, small
ballast type tanks at higher pressure than system pressure, one
filled with H2 and another filled with CO have an input located at
the common input to the one or more methanol synthesis reactors.
The exact ratio of Hydrogen to Carbon monoxide can be optimized by
a control system receiving analysis from monitoring equipment on
the compositions of syngas exiting the biomass gasifier 314 and
catalytic converters 316 and causing the ballast tanks to insert H2
or CO to optimize the ratio. The methanol produced by the one or
more methanol synthesis reactors is then processed in a methanol to
gasoline process.
[0057] The liquid fuel produced in the integrated plant may be
gasoline or another such as diesel, jet fuel, or some alcohols.
[0058] The torrefaction unit 312 may have its own several discrete
heating stages. Each heating stage is set at a different operating
temperature, rate of heat transfer, and heating duration, within
the unit in order to be matched to optimize a composition of the
non-condensable gases and condensable volatile material produced
from the biomass in that stage of the torrefaction unit 312. Each
stage has one or more temperature sensors to supply feedback to a
control system for the torrefaction unit 312 to regulate the
different operating temperatures and rates of heat transfer within
the unit.
[0059] Volatiles and char may be produced by slow pyrolysis of wood
via the process as follows: [0060] The compositions and yields of
volatile products are different in different temperature ranges.
Insert all biomass materials [0061] The composition of volatile
products from hardwoods is essentially the same in other hardwoods,
as the volatiles from softwoods are essentially comparable as other
soft woods, but volatiles from softwoods differ from volatiles from
hardwoods. [0062] Slow pyrolysis at moderate temperatures is
preferred to maximize the production of gas and char. [0063] Rapid
pyrolysis at high temperatures is preferred to maximize the
production of liquid and minimize char. [0064] The process is
endothermic up to approximately 280.degree. C., at which point an
exothermic reaction begins and continues to a temperature of
approximately 380.degree. C., where the process once again trends
back to endothermic. The stages of carbonization of wood in six
phases in an example torrefaction unit are summarized in Table 1 in
FIG. 4. A separation of the mixture of volatile materials occurs in
these six stages. Note, a similar set of off-gases can occur if the
TMP process uses steam temperatures of 200 degrees C. or more.
[0065] The effects of flash, fast, and slow pyrolysis differ on the
composition of volatile products obtained at different temperature
ranges, room temperature-300.degree. C., 300-400.degree. C., and
400-500.degree. C. Within a specific temperature range, flash,
fast, and slow pyrolysis produce different volatile products within
each range, consistent with the stages, but the overall list of all
the compounds obtained from wood by using different heating rates
were the same. Distillation curves for a composition of extractives
from hardwood, softwood, and TMP pulp may differ in the percent
generation of Non-condensables, Condensables, and Char at different
temperatures, rates of heating, and durations of heating. Thus,
softwood can be heated in different stages such as 200 degrees C.,
200-300, 300-400, 400-500, 500-600, 600-700, and 700 to 800.
Hardwood and Thermal mechanical pulp can also be heated in these
different stages to obtain a different composition and yield of
extractives from the hardwood, softwood, and TMP pulp. The volatile
materials from these different biomass types and processes may be
used as feed stocks.
[0066] FIG. 5 illustrates a flow schematic of an embodiment for the
radiant heat chemical reactor configured to generate chemical
products including synthesis gas products. The multiple shell
radiant heat chemical reactor 514 includes a refractory vessel 534
having an annulus shaped cavity with an inner wall. The radiant
heat chemical reactor 514 has two or more radiant tubes 536 made
out of a solid material. The one or more radiant tubes 536 are
located inside the cavity of the refractory lined vessel 534.
[0067] The exothermic heat source 538 heats a space inside the
tubes 536. Thus, each radiant tube 536 is heated from the inside
with an exothermic heat source 538, such as regenerative burners,
at each end of the tube 536. Each radiant tube 536 is heated from
the inside with fire and gases from the regenerative burners
through heat insertion inlets at each end of the tube 536 and
potentially by one or more heat insertion ports located in between
the two ends. Flames and heated gas of one or more natural gas
fired regenerative burners 538 act as the exothermic heat source
supplied to the multiple radiant tubes at temperatures between
900.degree. C. and 1800.degree. C. and connect to both ends of the
radiant tubes 536. Each tube 536 may be made of SiC or other
similar material.
[0068] One or more feed lines 542 supply biomass and reactant gas
into the top or upper portion of the chemical reactor 514. The feed
lines 542 for the biomass particles and steam enter below the entry
points in the refractory lined vessel 534 for the radiant tubes 536
that are internally heated. The feed lines 112 are configured to
supply chemical reactants including 1) biomass particles, 2)
reactant gas, 3) steam, 4) heat transfer aid particles, or 5) any
of the four into the radiant heat chemical reactor. A chemical
reaction driven by radiant heat occurs outside the multiple radiant
tubes 536 with internal fires. The chemical reaction driven by
radiant heat occurs within an inner wall of a cavity of the
refractory lined vessel 534 and an outer wall of each of the one or
more radiant tubes 536.
[0069] The chemical reaction may be an endothermic reaction
including one or more of 1) biomass gasification
(CnHm+H20.fwdarw.CO+H2+H20+X), 2) and other similar hydrocarbon
decomposition reactions, which are conducted in the radiant heat
chemical reactor 514 using the radiant heat. A steam (H2O) to
carbon molar ratio is in the range of 1:1 to 1:4, and the
temperature is high enough that the chemical reaction occurs
without the presence of a catalyst.
[0070] The torrefied biomass particles used as a feed stock into
the radiant heat reactor design conveys the beneficial effects of
increasing and being able to sustain process gas temperatures of
excess of 1300 degrees C. through more effective heat transfer of
radiation to the particles entrained with the gas, increased
gasifier yield of generation of syngas components of carbon
monoxide and hydrogen for a given amount of biomass fed in, and
improved process hygiene via decreased production of tars and C2+
olefins. The control system for the radiant heat reactor matches
the radiant heat transferred from the surfaces of the reactor to a
flow rate of the biomass particles to produce the above
benefits.
[0071] The control system controls the gas-fired regenerative
burners 538 to supply heat energy to the chemical reactor 514 to
aid in causing the radiant heat driven chemical reactor to have a
high heat flux. The inside surfaces of the chemical reactor 514 are
aligned to 1) absorb and re-emit radiant energy, 2) highly reflect
radiant energy, and 3) any combination of these, to maintain an
operational temperature of the enclosed ultra-high heat flux
chemical reactor 514. Thus, the inner wall of the cavity of the
refractory vessel and the outer wall of each of the one or more
tubes 536 emits radiant heat energy to, for example, the biomass
particles and any other heat-transfer-aid particles present falling
between an outside wall of a given tube 536 and an inner wall of
the refractory vessel. The refractory vessel thus absorbs or
reflects, via the tubes 536, the concentrated energy from the
regenerative burners 538 positioned along on the top and bottom of
the refractory vessel to cause energy transport by thermal
radiation and reflection to generally convey that heat flux to the
biomass particles, heat transfer aid particles and reactant gas
inside the chemical reactor. The inner wall of the cavity of the
thermal refractory vessel and the multiple tubes 536 act as
radiation distributors by either absorbing radiation and
re-radiating it to the heat-transfer-aid particles or reflecting
the incident radiation to the heat-transfer-aid particles. The
radiant heat chemical reactor 514 uses an ultra-high heat flux and
high temperature that is driven primarily by radiative heat
transfer, and not convection or conduction.
[0072] Convection biomass gasifiers used generally on coal
particles typically at most reach heat fluxes of 5-10 kW/m 2. The
high radiant heat flux biomass gasifier will use heat fluxes
significantly greater, at least three times the amount, than those
found in convection driven biomass gasifiers (i.e. greater than 25
kW/m 2). Generally, using radiation at high temperature (>950
degrees C. wall temperature), much higher fluxes (high heat fluxes
greater than 80 kW/m 2) can be achieved with the properly designed
reactor. In some instances, the high heat fluxes can be 100 kW/m
2-250 kW/m 2.
[0073] Next, the various algorithms and processes for the control
system may be described in the general context of
computer-executable instructions, such as program modules, being
executed by a computer. Generally, program modules include
routines, programs, objects, components, data structures, etc. that
perform particular tasks or implement particular abstract data
types. Those skilled in the art can implement the description
and/or figures herein as computer-executable instructions, which
can be embodied on any form of computer readable media discussed
below. In general, the program modules may be implemented as
software instructions, Logic blocks of electronic hardware, and a
combination of both. The software portion may be stored on a
machine-readable medium and written in any number of programming
languages such as Java, C++, C, etc. The machine-readable medium
may be a hard drive, external drive, DRAM, Tape Drives, memory
sticks, etc. Therefore, the algorithms and controls systems may be
fabricated exclusively of hardware logic, hardware logic
interacting with software, or solely software.
[0074] Some portions of the detailed descriptions above are
presented in terms of algorithms and symbolic representations of
operations on data bits within a computer memory. These algorithmic
descriptions and representations are the means used by those
skilled in the data processing arts to most effectively convey the
substance of their work to others skilled in the art. An algorithm
is here, and generally, conceived to be a self-consistent sequence
of steps leading to a desired result. The steps are those requiring
physical manipulations of physical quantities. Usually, though not
necessarily, these quantities take the form of electrical or
magnetic signals capable of being stored, transferred, combined,
compared, and otherwise manipulated. It has proven convenient at
times, principally for reasons of common usage, to refer to these
signals as bits, values, elements, symbols, characters, terms,
numbers, or the like. These algorithms may be written in a number
of different software programming languages. Also, an algorithm may
be implemented with lines of code in software, configured logic
gates in electronic circuitry, or a combination of both. The
control system uses the software in combination with integrated
logic chips in hardware to control the system.
[0075] It should be borne in mind, however, that all of these and
similar terms are to be associated with the appropriate physical
quantities and are merely convenient labels applied to these
quantities. Unless specifically stated otherwise as apparent from
the above discussions, it is appreciated that throughout the
description, discussions utilizing terms such as "processing" or
"computing" or "calculating" or "determining" or "displaying" or
the like, refer to the action and processes of a computer system,
or similar electronic computing device, that manipulates and
transforms data represented as physical (electronic) quantities
within the computer system's registers and memories into other data
similarly represented as physical quantities within the computer
system memories or registers, or other such information storage,
transmission or display devices.
[0076] While some specific embodiments of the invention have been
shown the invention is not to be limited to these embodiments. For
example, the recuperated waste heat from various plant processes
can be used to pre-heat combustion air, or can be used for other
similar heating means. Regenerative gas burners or conventional
burners can be used as a heat source for the furnace. Alcohols C1,
C2 and higher as well as ethers that are formed in the
torrefication process may be used as a high value in boosting the
octane rating of the generated liquid fuel, such as gasoline.
Biomass gasifier reactors other than a radiant heat chemical
reactor may be used. The Steam Methane Reforming may be/include a
SHR (steam hydrocarbon reformer) that cracks short-chained
hydrocarbons (<C20) including hydrocarbons (alkanes, alkenes,
alkynes, aromatics, furans, phenols, carboxylic acids, ketones,
aldehydes, ethers, etc, as well as oxygenates into syngas
components. The invention is to be understood as not limited by the
specific embodiments described herein, but only by scope of the
appended claims.
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